With the rapid development of the display technology, touch panels (Touch Screen Panels) have gradually spread all over people's lives. Generally, touch panels can be classified into an add-on mode touch panel, an on-cell touch panel, and an in-cell touch panel according to the composition and structure. For the add-on touch panel, a touch panel and a liquid crystal display (LCD) are produced separately, and then they are attached together to form a liquid crystal display panel having a touch function. The add-on touch panel suffers from the drawbacks of a higher production cost, a lower light transmittance, a thicker module and so on. While for an in-cell touch panel, touch electrodes of the touch panel are embedded inside a liquid crystal display panel, so that overall thickness of the module can be thinned, and the production cost of the touch panel can be reduced greatly as well, and thus it gets the favor of the major panel manufactures.
With respect to an in-cell touch panel, detection of touch location of a finger is achieved by using the principle of mutual capacitance or self-capacitance. A plurality of self-capacitive electrodes disposed in the same layer and insulated from each other may be arranged in the touch panel by using the principle of self capacitance. When a human body does not touch the panel, the capacitance born on each self-capacitive electrode is a fixed value. When a human body contacts the panel, the capacitive born on a corresponding self-capacitive electrode is the fixed value plus the body capacitance. With the touch detection chip, the touch location can be judged by detecting the change of capacitance value of each self-capacitive electrode in a touch period. In view of the fact that the body capacitance can act on all self capacitances, as compared with the mode in which the body capacitance can merely act on the projective capacitance in mutual capacitances, the amount of touch change caused by touch of a human body with the panel will be larger than that of a touch panel produced by using the principle of mutual capacitance. So, relative to a touch panel with mutual capacitance, the signal to noise ratio of touch can be effectively raised by a touch panel with self capacitance. Thus, the accuracy of touch sensing is enhanced.
However, when an in-cell touch panel is produced generally, it is required that additional touch-control chips and circuit boards be provided for touch-control function. Thus, although thickness of the whole module can be cut down with this design, the entire cost is promoted greatly.